title: Longer-term vision outcomes and complications with the Boston type 1 keratoprosthesis at the University of California, Davis.
abstract: OBJECTIVE
  To evaluate retention of visual acuity and development of complications after Boston type 1 keratoprosthesis implantation over a longer follow-up period than previously reported.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Forty eyes of 35 patients who underwent Boston type 1 keratoprosthesis surgery at the University of California, Davis, between 2004 and 2010.
  
  
  METHODS
  Preoperative, intraoperative, and postoperative parameters were collected and analyzed.
  
  
  METHODS
  Best-corrected visual acuity (BCVA) and postoperative complications.
  
  
  RESULTS
  Preoperative visual acuity ranged from 20/150 to light perception and was ≤20/400 in 38 eyes (95%). Preoperative diagnoses included failed corneal transplants (19 eyes, 47.5%), chemical injury (10 eyes, 25%), and aniridia (5 eyes, 12.5%). Mean follow-up duration was 33.6 months (range, 5-72 months). Of 36 eyes followed for ≥1 year, 32 eyes (89%) achieved postoperative BCVA ≥20/200. Of eyes that achieved BCVA ≥20/200, at last follow-up, 19 of 32 eyes (59%) followed for ≥1 year retained BCVA ≥20/200; 16 of 27 eyes (59%) followed for ≥2 years retained BCVA ≥20/200; 7 of 14 eyes (50%) followed for ≥3 years retained BCVA ≥20/200; and 2 of 7 eyes (29%) followed for ≥4 years retained BCVA ≥20/200. End-stage glaucoma most commonly caused vision loss (7 of 13 eyes, 54%) when BCVA ≥20/200 was not retained (follow-up ≥1 year). Glaucoma was newly diagnosed in 11 eyes (27.5%); progression was noted in 9 eyes (22.5%). Glaucoma drainage device erosion occurred in 9 eyes (22.5%). Retroprosthetic membrane formed in 22 eyes (55%), 5 eyes (12.5%) developed endophthalmitis, 6 eyes (15%) developed corneal melt, 7 eyes (17.5%) underwent keratoprosthesis replacement, and 23 eyes (57.5%) required major surgery to treat postoperative complications. The initial keratoprosthesis was retained in 32 eyes (80%).
  
  
  CONCLUSIONS
  Keratoprosthesis implantation remains a viable option for salvaging vision. A significant number of patients lost vision over the postoperative course. Glaucoma and complications related to glaucoma surgery are significant challenges to maintaining good vision after keratoprosthesis surgery. Our study highlights the need for long-term follow-up and a team approach to management, and points to a more guarded long-term visual prognosis after surgery.
  
  
  BACKGROUND
  The author(s) have no proprietary or commercial interest in any materials discussed in this article.
authors.affiliation: U.C. Davis Health System Eye Center, University of California at Davis, Sacramento, California, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Greiner
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Li
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Mannis
mesh_terms: D000046:Academic Medical Centers; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001187:Artificial Organs; D002140:California; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003315:Cornea; D003316:Corneal Diseases / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D016896:Treatment Outcome; D014786:Vision Disorders / Q000534:rehabilitation; D014792:Visual Acuity / Q000502:physiology*